fix: Check for "rustup" rather than ".rustup" when checking for wasm32

When checking for wasm32 target we did check if the sysroot
contained ".rustup". While this covered the most common cases it didn't
work when using Docker. So checking for "rustup" instead covers both
cases.

src/build/wasm_target.rs

@@ -24,7 +24,7 @@ impl fmt::Display for Wasm32Check {
             let rustup_string = if self.is_rustup {
                 "It looks like Rustup is being used.".to_owned()
             } else {
-                format!("It looks like Rustup is not being used. For non-Rustup setups, the {} target needs to be installed manually. See https://rustwasm.github.io/wasm-pack/book/prerequisites/index.html#target-wasm32-unknown-unknown on how to do this.", target)
+                format!("It looks like Rustup is not being used. For non-Rustup setups, the {} target needs to be installed manually. See https://rustwasm.github.io/wasm-pack/book/prerequisites/non-rustup-setups.html on how to do this.", target)
             };
 
             writeln!(
@@ -111,9 +111,9 @@ fn check_wasm32_target() -> Result<Wasm32Check, Error> {
         })
     // If it doesn't exist, then we need to check if we're using rustup.
     } else {
-        // If sysroot contains .rustup, then we can assume we're using rustup
+        // If sysroot contains "rustup", then we can assume we're using rustup
         // and use rustup to add the wasm32-unknown-unknown target.
-        if sysroot.to_string_lossy().contains(".rustup") {
+        if sysroot.to_string_lossy().contains("rustup") {
             rustup_add_wasm_target().map(|()| Wasm32Check {
                 rustc_path,
                 sysroot,